Vitamin K the basics--what's new?

Area of Science:

• Biochemistry
• Neonatology
• Nutritional Science

Background:

• Hemorrhagic disease of the newborn remains a global concern, with limited understanding of vitamin K needs in term and preterm infants.
• Perinatal vitamin K transfer from mother to infant is minimal, making neonatal sources crucial.
• Neonatal vitamin K sources include prophylaxis, diet, and gut bacteria, with preterm infants receiving substantial amounts from medical interventions.

Purpose of the Study:

• To review vitamin K metabolism, its dependent proteins, and the vitamin K cycle in infants.
• To explore the importance of vitamin K for human health, particularly in preterm infants.
• To investigate the implications of elevated vitamin K serum concentrations in preterm infants.

Main Methods:

• Review of existing literature on vitamin K metabolism and neonatal sources.
• Analysis of vitamin K status in term and preterm infants based on current data.
• Examination of vitamin K-dependent proteins and the vitamin K cycle in the neonatal context.

Main Results:

• Little vitamin K crosses the placenta, and neonatal sources are limited.
• Preterm infants exhibit significantly higher vitamin K serum concentrations compared to adults and term infants.
• Elevated vitamin K epoxide reductase (VKOR) in preterm infants' serum is noted, though no toxicity has been reported.
• PIVKA-II is not a reliable marker for vitamin K deficiency in neonates.

Conclusions:

• Further research is needed on vitamin K requirements and the significance of elevated VKOR in preterm infants.
• Current understanding of vitamin K metabolism and status in neonates requires further investigation.
• Clinical indicators for vitamin K deficiency in infants may need re-evaluation.